In a case of performing PLC in various devices such as a personal computer (PC), a PLC modem is provided and coupled to a wiring that connects the device and a power line to each other (see Patent Documents 1 to 3).
In general, each of the various devices includes a power supply circuit that converts a voltage supplied from the outside of the device into a desired voltage.
Particularly, Patent Document 3 proposes that the power supply circuit and the PLC modem share component parts to thereby reduce the costs of the component parts.